A former manager at two of the world's biggest pizza delivery chains has lifted the lid on the secrets of the fast food giants.

The anonymous ex-employee, who claims to have worked at US branches of Papa John's for two years and Domino's for four months, shared his insider knowledge on Reddit this week.

Under the guise of his username, sikkerhet, the restaurant worker revealed what in his opinion each chain does best, the toppings he recommends if you want to get your money's worth, as well as the pizza he always avoids buying.

The anonymous former employee took part in a 'Ask Me Anything' Reddit thread and posted pictures online of his payslips as 'proof'

The former manager says he doesn't 'like pizza anymore' after working at both chains for more than two years.

But for those who are a fan, he says head to Papa John's if you value good quality ingredients, and to Domino's for better cheese.